Festo Ag & Co. Kg

Festo Ag & Co

Jan Bredau

Reinhard Keller

Jens Engelhardt

Roberto Gutierrez Gonzalez

In a method for error containment and diagnosis in a fluid power system the fluid volumetric flow in the overall system or at least a part thereof and the fluid pressure (P) is detected as a measurement quantity in each case during a duty cycle and is compared with stored references. In each case at the point in time of a deviation or a change in the deviation from the reference it is determined at which component or at which components (through) of the system an event has occurred influencing fluid consumption in order to recognize same as subject to error. Guide value quantities (Q/P) are derived from the respective volumetric flow values (Q) and the measured pressure (P) and are integrated or summated over the duty cycle to form guide values (KD), a corresponding guide value reference curve (KDref) as a reference being chosen from a stored selection matrix, which has the guide value reference curves (KDref) or time dependent guide values for different operating conditions.

Method for error containment and diagnosis in a fluid power system

In a method for error containment and diagnosis in a fluid power system the fluid volumetric flow of the overall system or at least a part thereof or a quantity dependent thereon is detected as a measurement quantity respectively during an operating cycle and is compared with stored references. In each case at the point in time of a deviation or change in the deviation from the reference the method finds at which component or at which components (through) in the system an event has occurred influencing the fluid consumption in order to then to recognize same as subject to error. In the case of such a deviation or change therein and the simultaneous occurrence of several activities influencing fluid consumption by several components (through) a process of exclusion is performed, in which during the following activities involving at least one of such components (through) a check is made to see whether a deviation or a change in the deviation has occurred, and in each of such further examination steps the components involved are excluded from such further examination, if no deviation or change in the deviation takes place.

A diagnostic device for at least one pneumatic valve actuator arrangement, comprises a pressure sensor, a volumetric flow sensor, a control means for producing control signals for the valve actuator arrangement and position sensors for detecting the position of at least one moving actuator member. The diagnostic device also includes a first diagnostic module for leak detection, a second diagnostic module for the detection of a choking effect in pneumatic supply and venting lines and at least one third diagnostic module for the detection of load and friction changes in the case of the moving actuator member and/or of valve switching faults, switching means being provided for deactivating the at least one third diagnostic module in the case of the detection of a fault by the first and/or second diagnostic module. Using this diagnostic device it is possible to detect, owing to cooperation of the diagnostic modules, faults and trouble conditions in an extremely systematic fashion both qualitatively and quantitatively.

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Esslingen, Germany

Jan Bredau